Cable tuner circuits are used to receive a television signal from a television signal provider and to tune into a single channel within the television signal in order to present audio and video information from that channel to an end user. Cable tuners that operate using a superheterodyne circuit for use in a superheterodyne method of processing television signal information are commonplace. A superheterodyne receiver converts a desired signal to an intermediate frequency (IF) for filtering using a fixed bandpass filter. Signals having been passed through the fixed bandpass filter are processed by a second primary component of the receiver. A fixed bandpass filter is preferred because the filter characteristics are more readily and precisely determinable and hence the desired signal is more readily distinguishable from noise and other unwanted signals. Surface acoustic wave (SAW) filters are exemplary of the state of the art fixed bandpass filters used in television tuners.
Another aspect of tuner design relates to power consumption and bandwidth of operation. It is well understood in electronic circuit design that there is a typical tradeoff between speed and power consumption. Faster circuits consume more power and slower circuits consume less. Consequently, as the bandwidth for TV signals increases, the power consumption of the tuners increases. This increases heat dissipation and is therefore undesirable.
Furthermore, when tuners are active in a television, they are constantly consuming electrical power. This constant power consumption results in heating of the tuner circuit, which causes stress on the circuit components used to provide tuner functionality. A need therefore exists to enable and disable portions of the tuner circuit when they are not being utilized in order to reduce the power consumption of the tuner circuit.
It is therefore an object of the invention to provide a tuner circuit that implements executing of control loops in order to facilitate enabling and disabling circuit portions thereof to provide reduced power consumption.